fix: Vue SPA catch-all takes priority over legacy Twig routes

Without priority:1, Symfony matched legacy controllers (e.g. app_activity at /activity)
before the vue_app catch-all on hard reload. Now vue_app matches first for all paths
except /api/* and /legacy* which still route to Symfony controllers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config/routes.yaml

@@ -11,4 +11,5 @@ vue_app:
         template: 'vue/index.html.twig'
         req: ''
     requirements:
-        req: ".*"
+        req: "^(?!api/|legacy).*"
+    priority: 1